mirror of https://github.com/stella-emu/stella.git
Made the SUPERbank bankswitching code a little easier to follow, and
fixed a bug in the startup bank. According to the documentation, it should always start in the last bank. git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@1410 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba
This commit is contained in:
stephena
parent
6baa7c8311
commit
897e05d58a
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@ -23,16 +23,15 @@
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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CartridgeSB::CartridgeSB(const uInt8* image, uInt32 size)
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: mySize(size)
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: mySize(size),
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myLastBank((mySize>>12)-1)
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{
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// Allocate array for the ROM image
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myImage = new uInt8[mySize];
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// Copy the ROM image into my buffer
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for(uInt32 addr = 0; addr < mySize; ++addr)
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{
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myImage[addr] = image[addr];
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}
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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@ -44,8 +43,8 @@ CartridgeSB::~CartridgeSB()
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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void CartridgeSB::reset()
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{
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// Upon reset we switch to bank 0
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bank(0);
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// Upon reset we switch to the last bank
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bank(myLastBank);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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@ -60,19 +59,17 @@ void CartridgeSB::install(System& system)
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// Get the page accessing methods for the hot spots since they overlap
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// areas within the TIA we'll need to forward requests to the TIA
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myHotSpotPageAccess0 = mySystem->getPageAccess(0x0800 >> shift);
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myHotSpotPageAccess1 = mySystem->getPageAccess(0x0900 >> shift);
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myHotSpotPageAccess2 = mySystem->getPageAccess(0x0A00 >> shift);
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myHotSpotPageAccess3 = mySystem->getPageAccess(0x0B00 >> shift);
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myHotSpotPageAccess4 = mySystem->getPageAccess(0x0C00 >> shift);
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myHotSpotPageAccess5 = mySystem->getPageAccess(0x0D00 >> shift);
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myHotSpotPageAccess6 = mySystem->getPageAccess(0x0E00 >> shift);
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myHotSpotPageAccess7 = mySystem->getPageAccess(0x0F00 >> shift);
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myHotSpotPageAccess[0] = mySystem->getPageAccess(0x0800 >> shift);
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myHotSpotPageAccess[1] = mySystem->getPageAccess(0x0900 >> shift);
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myHotSpotPageAccess[2] = mySystem->getPageAccess(0x0A00 >> shift);
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myHotSpotPageAccess[3] = mySystem->getPageAccess(0x0B00 >> shift);
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myHotSpotPageAccess[4] = mySystem->getPageAccess(0x0C00 >> shift);
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myHotSpotPageAccess[5] = mySystem->getPageAccess(0x0D00 >> shift);
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myHotSpotPageAccess[6] = mySystem->getPageAccess(0x0E00 >> shift);
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myHotSpotPageAccess[7] = mySystem->getPageAccess(0x0F00 >> shift);
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// Set the page accessing methods for the hot spots
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System::PageAccess access;
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for(uInt32 i = 0x0800; i < 0x0FFF; i += (1 << shift))
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{
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access.directPeekBase = 0;
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@ -81,48 +78,25 @@ void CartridgeSB::install(System& system)
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mySystem->setPageAccess(i >> shift, access);
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}
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// Install pages for bank 0
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bank(0);
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// Install pages for startup bank
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bank(myLastBank);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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uInt8 CartridgeSB::peek(uInt16 address)
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{
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address = address & (0x17FF+(mySize>>12));
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// Switch banks if necessary
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if ((address & 0x1800) == 0x0800) bank(address & ((mySize>>12)-1));
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if ((address & 0x1800) == 0x0800)
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bank(address & myLastBank);
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if(!(address & 0x1000))
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{
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switch (address & 0x0F00)
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{
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case 0x0800:
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return myHotSpotPageAccess0.device->peek(address);
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break;
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case 0x0900:
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return myHotSpotPageAccess1.device->peek(address);
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break;
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case 0x0A00:
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return myHotSpotPageAccess2.device->peek(address);
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break;
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case 0x0B00:
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return myHotSpotPageAccess3.device->peek(address);
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break;
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case 0x0C00:
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return myHotSpotPageAccess4.device->peek(address);
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break;
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case 0x0D00:
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return myHotSpotPageAccess5.device->peek(address);
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break;
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case 0x0E00:
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return myHotSpotPageAccess6.device->peek(address);
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break;
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case 0x0F00:
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return myHotSpotPageAccess7.device->peek(address);
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break;
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default:
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break;
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}
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// Because of the way we've set up accessing above, we can only
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// get here when the addresses are from 0x800 - 0xFFF
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int hotspot = ((address & 0x0F00) >> 8) - 8;
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return myHotSpotPageAccess[hotspot].device->peek(address);
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}
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return 0;
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@ -132,41 +106,17 @@ uInt8 CartridgeSB::peek(uInt16 address)
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void CartridgeSB::poke(uInt16 address, uInt8 value)
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{
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address = address & (0x17FF+(mySize>>12));
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// Switch banks if necessary
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if ((address & 0x1800) == 0x0800) bank(address & ((mySize>>12)-1));
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if((address & 0x1800) == 0x0800)
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bank(address & myLastBank);
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if(!(address & 0x1000))
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{
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switch (address & 0x0F00)
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{
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case 0x0800:
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return myHotSpotPageAccess0.device->poke(address, value);
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break;
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case 0x0900:
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return myHotSpotPageAccess1.device->poke(address, value);
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break;
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case 0x0A00:
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return myHotSpotPageAccess2.device->poke(address, value);
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break;
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case 0x0B00:
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return myHotSpotPageAccess3.device->poke(address, value);
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break;
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case 0x0C00:
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return myHotSpotPageAccess4.device->poke(address, value);
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break;
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case 0x0D00:
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return myHotSpotPageAccess5.device->poke(address, value);
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break;
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case 0x0E00:
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return myHotSpotPageAccess6.device->poke(address, value);
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break;
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case 0x0F00:
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return myHotSpotPageAccess7.device->poke(address, value);
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break;
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default:
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break;
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}
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// Because of the way we've set up accessing above, we can only
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// get here when the addresses are from 0x800 - 0xFFF
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int hotspot = ((address & 0x0F00) >> 8) - 8;
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myHotSpotPageAccess[hotspot].device->poke(address, value);
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}
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}
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@ -179,7 +129,6 @@ void CartridgeSB::bank(uInt16 bank)
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myCurrentBank = bank;
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uInt32 offset = myCurrentBank * 4096;
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uInt16 shift = mySystem->pageShift();
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// uInt16 mask = mySystem->pageMask();
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// Setup the page access methods for the current bank
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System::PageAccess access;
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@ -135,22 +135,18 @@ class CartridgeSB : public Cartridge
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virtual void poke(uInt16 address, uInt8 value);
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private:
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// Indicates which bank is currently active
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uInt16 myCurrentBank;
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// The 128-256K ROM image and size of the cartridge
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uInt8* myImage;
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uInt32 mySize;
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// Indicates which bank is currently active
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uInt16 myCurrentBank;
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// Indicates the last bank
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uInt16 myLastBank;
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// Previous Device's page access
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System::PageAccess myHotSpotPageAccess0;
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System::PageAccess myHotSpotPageAccess1;
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System::PageAccess myHotSpotPageAccess2;
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System::PageAccess myHotSpotPageAccess3;
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System::PageAccess myHotSpotPageAccess4;
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System::PageAccess myHotSpotPageAccess5;
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System::PageAccess myHotSpotPageAccess6;
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System::PageAccess myHotSpotPageAccess7;
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System::PageAccess myHotSpotPageAccess[8];
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};
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#endif
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